Method of and apparatus for forming molded pulp articles



July 18, 1933. w H RANDALL 1,918,782

METHOD OF AND APPARATUS FOR FORMING MOLDED PULP ARTICLES Filed Aug. .'51, 1931 2 Sheets-Sheet l l b21/elder Wlteralzdall July 18, 1933. w. H. RANDALL METHOD OF AND APPARATUS FOR FORMING MOLDED PULP ARTICLES Filed Aug. 3l, 1931 2 Sheets-Sheet 2 W Atta/magy Patented July 18, 1933 UNITED STATES PATENT carica.

WALTER n. RANDALL, or wA'rEavILLn, nmz, Assronolrn'y nsmr Assrcmmnrs. 'ro Imm 'rnUs'r conm, or ron'rLAND, mim, A conronA'rIoN or nml.

TRUSTEE HETBODOF AND APPARATUS FOR IOBIING MOLDED PULP ARTICLES Application led August 31, 1931. Serial llo. 560,438.

This invention 'involves machines and methods for forming a multi-la er, diem'olded, pulp article, such as a p ate, dish or other container, and is distinguished from prior multi-layer formation machines and methods in that in my present invention the formation process is an intermittent rather than a continuously rotary forming process.

article being so controlled as to permit the article structure to be varied as required by changing commercial specifications or other conditions.

These and various other features of advantages which will appear more fully hereinafter, are attained by the machine vand method constituting the subject matter of -my present invention. The construction and o eration of such machine and the manner o practicing my method are described and illustrated in the accompanying specification and drawings and the characteristic features of novelty are particularly pointed lout in the appended claims.

In the drawings I have shown rather dia- `grammatically a form of apparatus for the practice of my method which I have found ighly satisfactory under actual service con# ditions. Such apparatus is purposely shown schematic in order to avoid' o scuring the underlying broad principles of my invention by details of machine construction not really necessary to a complete understanding of the fundamentals of my invention.

ing the interlocked layers of the integral In such drawings.:- Fig: 1 is a vertical section throu h a formmg 1e and associated parts an showin the relative positions of the parts at whicE may be regarded as an intermediate stage of the molding cycle.

`F1g 2 is a similar view showing a modilication, and

Figs. 3 to 10 inclusive are kvertical sections showing the relative positions of the appa- 50 ratus il ustrated in Fig. 1 at successive stages in the molding cycle. 4

I have indicated at 1 aforming die and at 2 a recelving die onto which the article formed on the forming die is adapted to be trans- 55 ferred 'for subsequent treatment. For the purposes of this application, however, the die 2 may be regarded simply as a holding or Yreceiving die to take the formed article from the forming die. v 7 The dies 1 and 2 are adapted to be moved 1n properly timed relation to each other by means of any suitable motion transmittin connections (not shown). As contemplated herein, such movement is an intermittent 7.5 I

movement, the forming die 1 reciprocating in the cylinder 3 during the forming process and .the receiving die 2 at the proper time movlng towards and pausing opposite the die 1 in order to permit the formed article pn said forming die to be transferred thereo.

Thus the movement of the die 2 is also an intermittent movement, but in so far as the fundamental principles of molding are concerned, such intermittent movement of the die 2 may be either a sliding rectilinear motion or such die may rotate intermittently through an orbit which is intersected b the line of reciprocation of the forming ie. 1, the transfer die 2 pausing when aligned with the die 1 for the purpose of permittln transfer of the formed article from the ie 1 to the die 2, and after such transfer has taken place, continuing its travelwhereby to carry the formed artlcle to some other station where it is subjected to further treatment, as for example, a drying treatment.

The forming d1e 1 'is of usual construction in so far as its pulp molding surface is con- 100 suitable mesh.

The formin die 1 lits within the cylinder 3 as a piston, ing provided with a hollow lunger or stem 4 y means of which it ma be reciprocated in said c linder and throug which suction is maintained in any suitable manner.

The cylinder is stationarily mounted on a suitable base 5 which also constitutes a support for a fixed pulp tank 6 enclosing said cylinder and having intermittent communication therewith through an annular series of inlet ports 7 formed in the cylinder wall and controlled by the position of the forming die 1 which thus acts as a slide valve to open or close said ports.

The materials which are to constitute the several deposits or layers of the composite article are admitted under conditions of proper control through inlet i:pipes 8 and 9 discharging, respectively, into e pulp tank and cylinder.

The tank 6 is formed as at 10 to permit overflow into an overflow pipe 12 controlled by a manually adjustable gate 11 which may conveniently be a simple slide valve adjustable within the tank to open or close said overflow outlet 10. The inlet of stock into the tank through pipe 8 is continuous and in suicient volume to maintain an overflow at 12 irrespective of the position or timing of the forming die 1, and the overflow outlet 10. is of such dimension relative to the rate of inlet as to maintain ,a substantially constant pulp level in the tank 6 at all times and in all ositions ofthe formi die.

or the purposes of this application, the material inlet pipe 8 to thetank 6 may be considered as supplying a relatively inexpensive stock, such as ground wood pulp, which constitutes the main body portion of the article, and the inlet pipe 9 into the cylinder 3 may be considered as suppl ing a higher grade lining stock, such as c emical pulp, which may or may not be bleached, and which forms the lining for the body stockl introduced through the pipe 8.

The admission of the lining stock into the cylinder through pipe 9 is controlled by any suitable valve 13 operating in pro rly timed relation to the movement of t ev orming die through any suitable motion transmitting connections, of which a portion thereof is indicated at 14.

The tank 6 is adapted continuously to be supplied with the low grade body-forming material B through pipe 8, such material as is not needed for the forming operation overflowing through port 10 into the overflow pipe 12, and the valve 13 controlling the admission of the high grade lining stock L through pipe 9 to the cylinder 3 is adapted to be opened to admit a predeperiodicall barge of such lining stock to the 'tion uof Fi 4, in which` position it b ocks the ports' which connect cylinder 3 with tank 6 and thus prevents the low-grade body stockv B from pipe 8-which is continuously being supplied to the tank from entering said cylinder. At this time, the valve 13 is automatically opened and a predetermined charge of the high grade lining stock L is admitted through ipe 9 into cylinder 3, depositing as a layer o predetermined depth on the forming face of the die 1 whereupon said valve y nnmediately closes.

The die 1 remains in the position of Fig. 4 for a suicient time to allow the lining stock L either partially or wholly, as desired, to drain and form vauch layer on, the die (Fig. 5). Where interfelting of such lining layer with the body layer is wanted., drainage is not completed before the bod stock is admitted, the die 1 moving to t e position of Fig. 6, in which position the ports 7 are uncovered, to admit a lcharge of the low-grade body stock B into the c linder 3 from the tank 6 while the lining ayer is still draining. Such body stock therefore mer or interfelts with the liningA stock left in the cylinder and net yet completely deposited on t e die 1. Under such circumstances, the formation process is continuous, starting immediately after the admission of the llning stock and continuing until all of the body stock is deposited on the forming die, so that at the time that the ound ,wood body stock is admitted and w ile it is merging with the undeposited linin stock, the formation processis going on, t us insuring good interfelting of the two deposits. Where it is not necessary to have interfelting the 1ining stock ma be allowed entirely to drain before the b y stock is admitted, the layers being simply secured together by adhesion, which adhesion may be augmented if desired gy subsequent treatment, as by pressure and eat.

In either case the forming die thereafter moves to the position of Fig. 7. This is a completely drainin position, the body stock drain through t e die while the die is in this position until draining is completed so that the layer of body stock, of the desired thickness, is merged with the lining layer on the die (Fig. 8). The degreevof thickness is accurately controllable by simply varying tank ,throng the time in which the ports 7 are uncovered and b varying the level of the stock in the adjustment of the gate 11.

The forming die then moves to the position of Fig. 9 which is the transferposition for the now formed article. At this time the receiving die 2 has moved into alinement with the forming die in order to receive the formed article and has paused in such position to permit the transfer of the formed article thereto.

.As the dies 1 and 2 separate (Fig. 10) the formed article A is deposited on the receivingdie for subsequent treatment, as a drying treatment in the further travel of the receivin`de, and the forming die repeats 'its.cycle. he low grade body stock B admltted into the cylinder 3 below the die 1 through the rts 7 while said die is in the positions of lgs. ports 6i the die 1 is raised or lowered. l

When the body stock is admitted intol the cylinder, -an agitation and mixing of the same occurs with the unde osited lining stock therein, resulting in a esirable interfelting or interlacing action between the two kinds of stock so that they are interlocked with each other as a practically homogeneous article.

The actual transfer of the formed article from the forming die to the transfer die may Vwithin the hollow stem 4 of the forming die.

In operation, the drain pipe 4 is emptied of the water therein between each formation cycle. At the start, of a formation cycle, vacuum is a plied to the pipe 17. Such vacuum imme iately withdraws the air from underneath the forming' die and also all air in pipe 4 above the check valve 4 said check valve being held securely closed byV said vacuum.

During the formation eriod, all entrapped air in the pulp stoc or which ma be underneath the die is removed throug pipe 17, the upper openend of said ipgipe having a cap 18 thereon which so shiel it as to prevent any water from entering said pi and being Withdrawn with the air.

iIehe water of formation discharges by gravity down the pipe 4 and lays against the trap at the check valve 4. This condition continues until the time.u of transfer of. the article from the die 1 to the die 2 at which time the vacuum is cut from the pipe 17 and 7 8, 9 and 10 is circulated through near the -,bottom of the cylinder asV a blast of air sent through said ipe. 'This blast of air performs the double gu transferring thearticle tothe receiving die 2 and adding pressure to the water in the pipe 4 so as to blow it out through the check valve 4 and free the pi of water.

The transfer d1e 2 may also be provided with a suction connection indicated at 16 b means of which the transferred article wi be held thereon after the di se arate.

In the modification shown in ig. 2 the inlet pipes 19 and 20 are both provided with control valves 21 and 22 respectively, which through suitable operating connections, a portion' of which is indicated at 23 and 24 are opened and closed in properly-timed relation to each other so as to admit into the cylinder 3 predetermined charges of body and lining stocks. v

The formation cycle in vthisernbodiment of my invention is generally similar to that deta1led in Figs. 3 et seq., the lining stock being first admitted through pipe .20 and drainin as a la er on the formlng die, after whic the b y layer is admitted through pipe 19 onto said lining layer and allowed to Vdrain and merge therewith. y

The forming die is then moved up to the receiving die 2 which is now alined with and aused opposite to the forming die and the ormed article transferred thereto.

In the embodiment of Fig. 2, however, the

nction of tank 6, ports 7 and overfiow 12 have been re- -dii'erent grades, it will be understood that l this treatment is purely for purposes of disclosure, and that Imay admit through the pipes 8 and 9'or 19 and 20 any materials which are capable of being united to form a composite article. Such union of the several deposits may be obtained by interfelting or by adhesion, due tov subsequent processing, as by drying under pressure and high temperatures.

similarly it winbe understood .that while I have referred to the article so formed 4as tion between successive deposits.

In other words, the resultant article may not be a layered article at all, except in so far as differences in color or fibre characteristic may be Idetected in the different depths of the interlocked fibre deposits constituting the article.

Various other modifications in the machine and method may obviously be made within the spirit and scope of my invention as defined by the appended claims.

solution is imposed upon said first solution before said first solution is completely deposited whereby to form a substantially integral article on said die, and in finally moving said forming die into a position in which the.l

formed article may be removed therefrom.

2. The tank, die and cylinder formation method which consists in successively depositing u on a foraminous forming die intermittent y movable within said cylinder aqueous pulp solutions of different characteristic and in such relation to each other and to the movement of the die that said second solution is interfelted with said first solution before said first solution is completely deposited whereby to form a substantiallyintegral article on said die, in controlling the admission of said second solution into said cylinder from said tank by the movement of said die in said cylinder, and in finally moving said forming die into a position in which the formed article may be removed therefrom.

3. The tank, die and cylinder formation method, which consists in depositing upon a foraminous die intermittently movable within said cylinder an aqueous pulp solution while admitting into a tank enclosing such cylinder a second solution of different fibre-characteristic, in moving said die in said cylinder to admit said second solution uinto said cylinder for deposit on said die before said first solution is completely deposited whereby to interfelt the two solutions as a substantially integral article, and in finally moving said forming die into a position in which the formed article may be removed therefrom.

- 4. In pulp molding apparatus, a tanky having a supply and an overflow for an aqueous pulp solution, va cylinder within said tank having a port opening into said tank, a timed supply for delivering an aqueous pulp solution of different characteristic to said cylinder, a forming die movable in said cylinder and acting as a slide valve to close and open said port, said die in one position closing said port and receiving a predetermined charge from said pulp supply to said cylindervand in another positionguncovering said port to permit a predetermined charge of pulp solution from said tank to be imposed upon said first depositand interfelt therewith before said first solution is completely deposited 5 upon said die, and means whereby said die may be thereafter moved into position to permit removal of the formed article.

5. In pul molding apparatus, a tank having a supp y and an overflow for an aqueous pulp solution, a cylinder within said tank having a port opening into said tank, a timed supply for elivering an aqueous .pulp solution of different characteristic to said cylinder, a forming die movable in said cylinder and acting as a slide valve to close and open said port, said die in one position closing said port and receiving a predetermined charge from said pulp supply to said cylinder andfin another position uncovering said port to permit a predetermined charge of pulp solution from said tank to be im osed upon said first deposit and interfelt t erewitli before said first solution is com letely deposited upon said die, and means w ereby said die may be thereafter moved into position to permit removal of the formed article, said means constitutin a suction connection whereby suction may maintained on said die during the formation process.

6. In pulp molding apparatus, a tank having a supply and an overflow for an aqueous pulp solution, a cylinder within said tank having a port opening into said tank, a timed supply for delivering an aqueous pulp solution of different characteristic to said c linder, a forming die movable in said cylinder and acting as a slide valve to close and open said port, said die in one position closing said port and receiving a predetermined charge from said pulp supply to said cylinder and in another position uncovering saidl port to permit a predetermined charge of pulp solution from said tank to be im upon said first deposit and interfelt therewith before said first solution is com letely deposited upon said die, means whereby said die may be moved into position to permit removal of the formed article, said means constituting a suction connection whereb ,suction may be maintained on said die uring the formation process, and means independent of said suction connection whereby the entrained water in said article may be partially withdrawn during the formation process.

7. In pulp molding apparatus, a tank having a supply and an overflow for an a ueous pulp solution, a cylinder within sai tank having a port opening into said tank, a timed supply for delivering an aqueous pulp solution of different characteristic to said cylinder, a. forming die movable in said cylinder and acting as a slide valve to close and IIB open said port, said die in one position closing said port and receiving a predetermined charge from said pulp supply to said cylinder and in another position uncovering said port to permit a predetermined charge of pulp solution from said tank to be imposed upon said first deposit and interfelt,

therewith, before said first solution is com- Va forming die movable therein, means for o inde ndently admitting into said cylinder letely deposited upon said die, means whereby said die may be moved into position to permit removal of the formed article, said means constituting a drainage connection for the water of sus nsion, and an independent connection w ereby suction may be maintained on said die during the formation process and whereby entrapped air beneath said die may be partially withdrawn during the formation process, said withdrawing means also constituting an air blast connection whereby theA formed article may be dislodged from said forming die at the end of the formation process.

8. In pulp molding apparatus, a base, a

vtank mounted on said base,.a pipe for continuously supplying an aqueous pul solution to said tank, a cylinder within said tank having a port opening into said tan'k, a timed supply for delivering an aqueouspulp solution of different characteristic into the upper end of said cylinder, a-nd a forming die movable in said cylinder and acting as a slide valve to close and open said port, said die in one position closing said port and receiving a predetermined charge from said pulp supply to said cylinder and inanother position uncovering .saidport to permit a predetermined charge of pulp solution from said tank to be imposed upon said first deposit and interfelt therewith before said first solution is completely deposited upon said die.

9. In pulp molding apparatus, a cylinder, a forming die movable therein, and means whereby independent aqueous pulp solutions may be introduced into said cylinder in such relation to each other that the second solution interfelts with the first solution on said die before said rst solution is completely deposited.

10. In pulp molding apparatus, a tank, a cylinder therein, and having a port adapted to communicate with said tank, a forming die movable in said cylinder and actingas a slide valve to cover and uncover said port, and means whereby independent aqueous pulp solutions may be introduced into said tank and cylinder in such relation to each other that the second solution interfelts with the first solution on said die before said first solution is completely deposited.

11. In pulp molding apparatus, a tank, a cylinder therein and having a port adapted to communicate with said tank, a forming die movable within said cylinder and acting as a slide valve to cover and uncover said port, and independent deliveries to said tank and cylinder for supplying independent aqueous pulp solutions thereto in such relation to each other than the second solution interfelts with the first solution on said die before said first solution is completely deposited. v A

12. In pulp molding apparatus, a cylinder,

for eposit on said die aqueous pul1 solutions of di'erent characteristics in su interfelts with the first solution on said die before said first solution is completely deposited, means whereby said Vformin die may be moved into a position in whic the formed .article may be removed therefrom, and means whereby suction ma -be maintained on said die while said eposits are formin thereon. y

13. npul moldin apparatus,acylinder, a forming 'e mova le'therein, means for independently admitting into said cylinder for deposit on said die successive aqueous pulp solutions of diii'erent characteristics in such relation to each other that the second solution interfelts -with the first solution on said die before said first solution is oompletely deposited, means whereby said formrela- .tion to each other that the second solution ing die may be moved into a position in which v the formed article may be removed there from, and means whereby suction may be maintained on said die while said deposits are forming thereon and the entrapped air beneath said die partially Withdrawn during the formation process.

14. In pulp molding apparatus, a cylinder, a forming die movable therein, means for independently admitting into ,said cylinder for deposit on said die successive aqueous pulp solutions of diierent characteristicsin such relation to each other that the second solution interfelts with the first solution on said die before said first solution is completely deposited, means whereby said forming die may be moved into a position in which the formed article may be removed therefrom, means whereby said die may be drained of the water of suspension, and

means independent of said drainage means whereby suction 'may be maintained in said die while said de osits-are formin thereon and the entrapped air beneath sai die partially withdrawn during formation process. 15. In pulp molding apparatus, a cylinder, a forming die movable therein, means for independently admittinginto said cylinder for deposit on said die successive aqueous pulp solutions of different characteristics in suc relation to each other that the second solution interfelts with the first solution on said die before said first solution is completely deposited, means whereby said forming die 4may be moved into a position in which the formed article may be removed therefrom, means whereby suction may be maintained on said die while said deposits are lforming thereon and the entrappe'd air beneath said die partially withdrawn during the formation process, said last-named means also constitut-v ing an air blast connection whereby the formed article may be dislodged by air blast ias from said forming die at the end of the formation process.

16. In pulp molding apparatus, a tank, a cylinder within saidtank, said tank and cylinder having a port connecting the same, a

lpiston movable within said cylinder and covering and uncovering said port, a supply .pi to said tank and a supply pi to said cy inder, said pipes sulplying in ependent aqueous pulp solutions o different characteristics, and a valve 'controlling said supply pipe to the cylinder and operating in timed relation to the movement of the ie in said cylinder.

`17. In pulp molding apparatus, 'a cylinder,

` a die moving therein, a pulp suppl for delivering an aqueous pulp solution into said cylinder in one position of said die, a pulp supply for delivering a second aqueous pulp solution of different characteristic into said cylinder and onto said first deposit in another position of said die whereby ultimatelyr to orm with said first deposit a substantially integral article on said die, and means for subsequently removing the article thus formed from said die.

into the cylinder, in depositing upon 2 Lampes tion a second pulp solution, in thereafter movin the die to a non-blocking position where y to admit a charge of the first solution from said tank to said cylinder for deposit on top of said second solution, and in finally moving said die to a transfer position wherein the now formed article may be removed from the die.

19. vIn the intermittent formation method of producing an integral molded pulp article from successive deposits of aqueous ulp solutions of different fibre characteristic which utilizes as the formation apparatus a tank, a cylinder ada ted to communicate therewith, and a foraminous forming or suction die intermittently movable in said cylinder and controlling the communication between said tank and cylinder, those steps which consist in admitting into the tank a first pulp solution, in moving the formin die into position to block entry of such soition from the tank into the cylinder, in depositing upon the forming die whil in said blocking position a second pulp solution,vin maintaining the die in such blocking position for a time suilicient to allow said second solution to partially or wholly drain, Ain thereafter movin the die to a vnon-blocking position where y 'to admit a charge of the first solution from said tank to said cylinder for deposit on said second solution, in thereafter moving the die to' a position wherein said first solution will drain and be merged with the second solution already deposited upon the die, and in finally 1 moving; said die to a transfer position wherein the now formed article may be removed from the die.

WALTER H. RANDALL. 

